Thoracic Motion Research Articles

Multimodal physiological correlates of dyspnea ratings during breath-holding in healthy humans.

Dyspnea is associated with fear and intense suffering and is often assessed using visual analog scales (VAS) or numerical rating scales (NRS). However, the physiological correlates of such ratings are not well known. Using the voluntary breath-holding model of induced dyspnea, we studied healthy volunteers to investigate the temporal relationship between dyspnea, the neural drive to breathe assessed in terms of involuntary thoracoabdominal movements (ITMs) and neurovegetative responses. Twenty-three participants (10 men; median [interquartile range] age 21 [20-21]) performed three consecutive breath-holds with the continuous assessment of dyspnea (urge-to-breathe) using a 10cm VAS, thoracic and abdominal circumferences measured with piezoelectric belt-mounted transducers, heart rate and heart rate variability (HRV), and galvanic skin response (GSR). Urge-to-breathe VAS at the onset of ITMs (gasping point) was identified visually or algorithmically. Urge-to-breathe VAS at the end of the breath-hold was 9.7 [8.6-10] cm. Total breath-hold duration was 93 [69-130]s. Urge-to-breathe VAS, ITM, heart rate, HRV, and GSR significantly increased during breath-hold. Urge-to-breathe VAS correlated with the magnitude of the thoracic and abdominal movements (rho = 0.51 and rho = 0.59, respectively, p < 0.001). The urge-to-breathe ratings corresponding with ITM onset were 3.0 [2.0-4.7] cm and 3.0 [1.0-4.0] cm for visual and algorithmic detection, respectively (p = 0.782). An urge-to-breathe VAS of 3cm (30% of full scale on a 10cm VAS) corresponds to a physiological turning point during the physiological response to voluntary breath-holding in healthy humans.

A Respiratory Sensor-Based Study of the Relationship between Voluntary Breathing Patterns and Aerobic and Anerobic Exercise Capacity—An Exploratory Applied Study

(1) Background: Exploring the relationship between spontaneous breathing patterns and aerobic and anerobic running exercise performance can greatly improve our understanding of optimizing physical fitness. Spontaneous breathing patterns refer to how the rhythm and depth of breathing affect performance and physical adaptation during exercise. (2) Methods: This study aimed to investigate this relationship by enrolling 240 college students (120 males and 120 females, aged 18–22). We evaluated their resting respiratory rate (RR), the combined total of abdominal and thoracic movements (AM+TM), the proportion of abdominal movement to the overall respiratory movement (AM/(AM+TM)), and the inhalation to exhalation ratio (I/E ratio). Additionally, their performance in a 50 m sprint (measuring anerobic capability), an 800- or 1000 m run (assessing mixed aerobic and anerobic capacity), and a 12 min distance run (evaluating aerobic capacity) was recorded. (3) Results: Our findings, through both correlational and comparative analyses, indicate that a larger AM+TM is predictive of a greater distance covered in the 12 min run, suggesting enhanced aerobic capacity. Interestingly, among female participants, a lower body mass index (BMI) coupled with a higher proportion of abdominal movement (AM/(AM+TM)) was linked to better performance in the 800 m run, indicative of superior mixed aerobic and anerobic capacities. These results imply that women with a larger tidal volume and those with a lower BMI but higher abdominal contribution to breathing at rest may exhibit better aerobic and mixed exercise capacities, respectively. (4) Conclusions: Based on these findings, we recommend that healthcare professionals and physical education instructors incorporate respiratory pattern assessments into their practices to potentially improve the physical health of their clients and students, with a particular emphasis on female populations. This study underscores the importance of understanding the intricate relationship between spontaneous respiratory patterns and exercise capabilities in enhancing overall physical fitness and health.

When more is more: Utilizing finite element analysis to assess chest wall injury stability after surgical stabilization of all rib fractures versus only a portion of the rib fractures.

Surgical stabilization of rib fractures (SSRF) continues to gain acceptance. Controversary exists around the number of rib fractures needing stabilization. We sought to analyze chest wall stability (CWS) after SSRF using finite element analysis (FEA) modeling in various rib fracture patterns, hypothesizing not stabilizing all fractures leaves the chest wall unstable. FEA thoracic model development was described previously. Two fracture patterns with three case scenarios each were defined for right ribs 4 to 9. Fracture Pattern 1; Case 1-all 6 ribs with lateral fractures and no stabilization; Case 2-all six fractures stabilized; Case 3-only fractures 5 to 7 were stabilized. Fracture Pattern 2; Case 4-all six ribs fractured in a flail pattern (anterior-lateral and posterior-lateral) and no stabilization; Case 5-all 12 fractures stabilized; Case 6-only six anterior-lateral fractures were stabilized. Three assessment criteria were used to quantify thoracic motion: normalized mean absolute error (NMAE), normalized root mean square error (NRMSE), and normalized interfragmentary motion (NIFM). Fracture Pattern 1: Case 1-NMAE and NRMSE analysis demonstrated significant loss of CWS up to 50% with left axial rotation; Case 2-CWS almost completely returned to nonfractured state; Case 3-CWS loss up to 37%. Fracture Pattern 2: Case 4-up to 49% of CWS lost with right axial rotation; Case 5-less than 3% CWS lost; Case 6-over 40% CWS lost. For both fracture patterns, when stabilizing all fractures, NIFM decreased by 95%. In Case 3, NIFM decreased by 56% and in Case 6, NIFM increased by 1% at the non-stabilized fracture line. Stabilizing all rib fractures significantly improves CWS. Not stabilizing both fractures of a flail segment worsens motion at the non-stabilized fractures. Therapeutic/Care Management; Level IV.

Physiological Regularity and Synchrony in Individuals with Gaming Disorder.

Individuals with gaming disorder (GD) show emotional dysregulation and autonomic dysfunction in daily life. Although studies have shown that the relaxation method of breathing exercise (BE) improves cardiopulmonary synchrony, the physiological regularity and synchrony of GD remain unclear. In this study, we investigated the regularities of pulse wave (PW), thoracic wall movement (TWM), and abdominal wall movement (AWM) using sample entropy (SE) and assessed the vascular-respiratory and TWM-AWM synchrony using cross-sample entropy (CSE). Twenty individuals with GD and 26 healthy control (HC) individuals participated in baseline, gaming, and recovery stages, both before and after BEs. The results showed that both groups had significantly higher SETWM, SEAWM, and CSETWM-AWM during gaming than baseline. Before BE, CSEPW-TWM and CSEPW-AWM during gaming were considerably higher in the GD group than in the HC group. Compared to before BE, both groups had decreased SETWM and CSETWM-AWM during gaming, particularly in the HC group. Online gaming may induce pulse wave and respiratory irregularities, as well as thoracic-abdominal wall movement asynchrony. Individuals with GD who engage in prolonged gaming periods may exhibit lower vascular-respiratory synchrony compared to the HC group. SETWM, SEAWM, CSETWM-AWM, CSEPW-TWM, and CSEPW-AWM may serve as biomarkers for assessing the risk of GD. BE may improve TWM regularity and vascular-respiratory synchrony during gaming, potentially alleviating addictive behavior.

Using markerless motion capture and musculoskeletal models: An evaluation of joint kinematics.

This study presents a comprehensive comparison between a marker-based motion capture system (MMC) and a video-based motion capture system (VMC) in the context of kinematic analysis using musculoskeletal models. Focusing on joint angles, the study aimed to evaluate the accuracy of VMC as a viable alternative for biomechanical research. Eighteen healthy subjects performed isolated movements with 17 joint degrees of freedom, and their kinematic data were collected using both an MMC and a VMC setup. The kinematic data were entered into the AnyBody Modelling System, which enables the calculation of joint angles. The mean absolute error (MAE) was calculated to quantify the deviations between the two systems. The results showed good agreement between VMC and MMC at several joint angles. In particular, the shoulder, hip and knee joints showed small deviations in kinematics with MAE values of 4.8∘, 6.8∘ and 3.5∘, respectively. However, the study revealed problems in tracking hand and elbow movements, resulting in higher MAE values of 13.7∘ and 27.7∘. Deviations were also higher for head and thoracic movements. Overall, VMC showed promising results for lower body and shoulder kinematics. However, the tracking of the wrist and pelvis still needs to be refined. The research results provide a basis for further investigations that promote the fusion of VMC and musculoskeletal models.

Towards automatic home-based sleep apnea estimation using deep learning

Apnea and hypopnea are common sleep disorders characterized by the obstruction of the airways. Polysomnography (PSG) is a sleep study typically used to compute the Apnea-Hypopnea Index (AHI), the number of times a person has apnea or certain types of hypopnea per hour of sleep, and diagnose the severity of the sleep disorder. Early detection and treatment of apnea can significantly reduce morbidity and mortality. However, long-term PSG monitoring is unfeasible as it is costly and uncomfortable for patients. To address these issues, we propose a method, named DRIVEN, to estimate AHI at home from wearable devices and detect when apnea, hypopnea, and periods of wakefulness occur throughout the night. The method can therefore assist physicians in diagnosing the severity of apneas. Patients can wear a single sensor or a combination of sensors that can be easily measured at home: abdominal movement, thoracic movement, or pulse oximetry. For example, using only two sensors, DRIVEN correctly classifies 72.4% of all test patients into one of the four AHI classes, with 99.3% either correctly classified or placed one class away from the true one. This is a reasonable trade-off between the model’s performance and the patient’s comfort. We use publicly available data from three large sleep studies with a total of 14,370 recordings. DRIVEN consists of a combination of deep convolutional neural networks and a light-gradient-boost machine for classification. It can be implemented for automatic estimation of AHI in unsupervised long-term home monitoring systems, reducing costs to healthcare systems and improving patient care.

Cardiorespiratory Response to Workload Volume and Ergonomic Risk: Automotive Assembly Line Operators’ Adaptations

Repetitive tasks can lead to long-term cardiovascular problems due to continuous strain and inadequate recovery. The automobile operators on the assembly line are exposed to these risks when workload volume changes according to the workstation type. However, the current ergonomic assessments focus primarily on observational and, in some cases, biomechanical methods that are subjective and time-consuming, overlooking cardiorespiratory adaptations. This study aimed to analyze the cardiorespiratory response to distinct workload volumes and ergonomic risk (ER) scores for an automotive assembly line. Sixteen male operators (age = 38 ± 8 years; BMI = 25 ± 3 kg·m2) volunteered from three workstations (H1, H2, and H3) with specific work cycle duration (1, 3, and 5 min respectively). Electrocardiogram (ECG), respiratory inductance plethysmography (RIP), and accelerometer (ACC) data were collected during their shift. The results showed significant differences from the first to the last 10 min, where H3 had its SDRRi reduced (p = 0.014), H1’s phase synchrony and H2’s coordination between thoracic and abdominal movements decreased (p &lt; 0.001, p = 0.039). In terms of ergonomic risk, the moderate-high rank showed a reduction in SDRRi (p = 0.037) and moderate-risk activities had diminished phase synchrony (p = 0.018) and correlation (p = 0.004). Thus, the explored parameters could have the potential to develop personalized workplace adaptation and risk assessment systems.

Body Position Dependent Participation of Abdominal and Thoracic Breathing Movements During the Breathing Cycle

Aims: Both abdominal and thoracic breathing movements play important roles in the mechanics of breathing, participating differently in various body positions with abdominal breathing having a greater role. Recent studies showed that an early proning position of awake, non-intubated patients during the COVID-19 pandemic, even during pregnancy (PMID: 32320506, PMID: 33309507, PMID: 34915799) significantly affected the ventilatory parameters and mortality of SARS-CoV-2 patients. Thus, we hypothesized that in different body positions the participation of abdominal (AB) and thoracic breathing (TB) during the complete respiratory cycle (CRC) is different. To test this, we measured the participation of AB and TB to the CRC in different body positions under resting conditions. Methods: In young participants (N=26) age between 18 and 24 (M=21.3±1.6), changes in abdominal and chest circumferences were measured using plethysmography respiratory belts, during inhalation and exhalation in standing (ST), sitting (SI), supine (SU), prone (PR), and all on fours (AF) body positions. Respiratory frequency was also measured. Results: In different positions, the contribution of AB and TB to CRC were significantly different (F(4,100)=4.999, p=0.004, η2p=0.17). AB was significantly higher than TB in all positions (p&lt;0.001). More specifically, AB gradually increased, while TB gradually decreased in the following order: SU(AB/TB) = 74.8±12.9%/25.2%, ST = 69±16%/31%, PR = 66.8±20.2%/33.2%, SI = 65.5±14.8%/34.5%, AF = 61.1±15.1%/38.9%. A significantly higher value was measured in the SU position compared to AF (p&lt;0.001) and SI (p=0.011) positions; PR and ST positions showed intermediate values, which were not significantly different from those yielded by either of the other positions. Respiratory frequency was similar in different body positions. Conclusions: These data show that different body positions significantly affect the participation of abdominal and thoracic breathing during resting condition, underscoring not only the importance of respiratory distress patients positioning during hospitalization, but its usefulness in developing a respiratory training plan for elite athletes to optimize their physical and mental performance in competitive sports. AK: Ministry of Innovation and Technology (MIT) of Hungary-NRDI TKP2020-NKA-17, TKP2021-EGA-37, and National Research, Development, and Innovation Offce (NKFIH) OTKA K 132596 K_19, and Hungarian Academy of Sciences, Post-Covid 2021-34, and HUN-REN-SU: 02068 of Hungary, JT: ÚNKP-22-4-II-SE-4 (JT), TKP2021-EGA-25. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

In vivo comparative assessments on pleural adhesive effects of three commercially available sealants

ObjectiveSurgical sealant, which is used for the reinforcement of suture lines, has been widely used in lung-resection surgeries with the aim of reducing postoperative morbidity; however, it may exacerbate surgical-site adhesion, creating the risks of restrictive thoracic movement and a difficult entrance for redo operation. We aimed to assess the pleural adhesive effects of 3 frequently used surgical sealants, (1) fibrin glue (fibrin), (2) a composite of polyethylene glycol and human serum albumin (PEG/HSA), and (3) bioabsorbable polyglycolic acid felt (PGA), in an in vivo setting. MethodsEighty-one rats were randomly assigned to 3 experimental groups—fibrin, PEG/HSA, and PGA. After intrapleural application of the sealants, the extent and severity of adhesion and inflammation were quantitatively compared among the 3 groups at 2, 4, and 8 weeks. ResultsThe scores for both the extent and severity of adhesion were significantly greater in the PGA group than the other 2 groups throughout postoperative period (P < .001 for all). Although both scores in the PES/HSA and fibrin groups were 0 at 2 weeks, the fibrin group showed significantly greater scores than the PES/HSA group thereafter (P < .001 for all). Trends in inflammation scores were similar of those of adhesion scores, favoring the PES/HSA group followed by the fibrin group (P < .001 for all). ConclusionsAmong 3 commonly used sealants, PEA/HSA showed least degree of adhesion/inflammation compared with fibrin and PGA, whereas PGA demonstrated greatest degrees of adhesion/inflammation throughout a postoperative course of 8 weeks in an in vivo model.

Maternal and neonatal effects of epidural levobupivacaine combined with fentanyl or sufentanil for elective cesarean-section in brachycephalic breeds

The aim of this study was to compare the safety and clinical efficacy of epidural levobupivacaine combined with fentanyl or sufentanil for bitches undergoing elective cesarean-section and the impact of these anesthetic protocols on neonatal viability. The anesthetic protocol consisted of intramuscular morphine (0.2 mg/kg), followed by an intravenous bolus of propofol, in a dose sufficient to allowed the puncture of the lumbosacral space. The dogs were randomly allocated to receive 0.5 % levobupivacaine plus fentanyl (2.5 µg/kg; LF: n = 9) or sufentanil (1 µg/kg; LS; n = 11). Maternal cardiorespiratory parameters were monitored at specific time points during surgery. Intraoperative propofol supplementation was based on the presence of head and/or thoracic limb movements. Neonatal reflex responses and the Apgar score (range 0-10 points) were assessed at 5 and 60 minutes after birth. Puppy mortality rate was recorded until 24 hours after birth. Data were analyzed using two-way ANOVA, Tukey's test, Wilcoxon signed rank test, and Fisher's exact test (P < 0.05). Intraoperatively, maternal cardiorespiratory variables and propofol requirements were similar between groups, with no detection of anesthetic complications. The puppy reflex responses did not differ between groups at any time point. The medians (range) of Apgar scores were lower (P = 0.016) in the LF [5 (1-9)] at 5 minutes in comparison with LS [6 (2-9)], while no intergroup differences were recorded at 60 minutes [LF = 8 (2-10); LS = 9 (6-10]. The total mortality rate was 4.1 %. In the LS group, no puppies died, while in the LF 8 % of the puppies died in the first 24 hours after birth (P = 0.11). Epidural levobupivacaine combined with fentanyl or sufentanil provided minimal maternal and neonatal adverse effects, but neither protocol enabled the performance of a C-section in 100 % of the French and English bulldogs, without propofol supplementation.

Effect of diaphragmatic stretch technique on thoracic excursion and pulmonary function in COPD patients: Study protocol for randomized controlled trial.

Limited airflow is a defining feature of COPD, a respiratory disease that frequently results in reduced thoracic movement and compromised lung function. The diaphragm, which is the main breathing muscle, is essential for healthy lung expansion and ventilation. The diaphragm muscle’s flexibility and mobility are intended to be enhanced via diaphragmatic stretching. This method can enhance respiratory health and assist in returning the diaphragm to its original state. Patients with COPD may benefit from improved lung expansion and ventilation because of this. The usefulness of integrating the diaphragmatic stretch approach with traditional chest physical therapy is not well-established. Thus, research is needed to ascertain how the diaphragmatic stretch technique affects lung function and thoracic excursion in COPD patients. This study aims to ascertain how the diaphragmatic stretch technique affects thoracic excursion and pulmonary function (FEV1, FVC, FEV1/FVC, FEF25%-75%, PEFR) in individuals with COPD. There will be 58 COPD patients enrolled in total for this trial; 29 will receive traditional chest physiotherapy along with the diaphragmatic stretch technique, and 29 will receive traditional chest physiotherapy exclusively. Two weeks will pass throughout the intervention. Prior to the intervention, pre-outcome measures will be evaluated, and two weeks later, post-outcome measures will be evaluated once more. The anticipated outcome of this study is that the diaphragmatic stretch technique can enhance thoracic excursion and improve pulmonary function just as well as traditional chest physiotherapy when used in conjunction with it.

Clinical correlates of respiratory disorders in patients with severe multiple sclerosis: A cross-sectional cohort

Background: Respiratory disorders remain incompletely described in multiple sclerosis (MS), even though they are a frequent cause of death. Methods: The objective was to describe respiratory disorders in MS patients with Expanded Disability Status Score (EDSS) ⩾ 6.5. Diaphragm dysfunction was defined by at least two of the seven criteria: clinical signs, inspiratory recruitment of neck muscles during wakefulness, reduced upright vital capacity (VC) < 80%, upright-to-supine VC ⩾ 15% of upright VC, decrease in Maximal Inspiratory Pressure < 60%, phasic activation of inspiratory neck muscles during sleep, and opposition of thoracic and abdominal movements during sleep. Cough weakness was defined by a peak cough flow < 270 L/min and/or need for cough assist. Sleep apnea syndrome was defined by an apnea–hypopnea index ⩾ 15. Results: Notably, 71 MS patients were included: median age 54 [48, 61] years; median disease duration 21.4 [16.0, 31.4] years. Of these, 52 patients had one or more respiratory disorders; diaphragm dysfunction was the most frequent (n = 34). Patients with diaphragm dysfunction and cough weakness were more disabled. The fatigue score and the cognitive evaluations did not differ between the groups. Five patients required non-invasive ventilation. Conclusion: Respiratory disorders are frequent in severe MS, mostly diaphragm dysfunction. Of interest, instrumental interventions are available to address these disorders.

Current Research Status of Respiratory Motion for Thorax and Abdominal Treatment: A Systematic Review.

Malignant tumors have become one of the serious public health problems in human safety and health, among which the chest and abdomen diseases account for the largest proportion. Early diagnosis and treatment can effectively improve the survival rate of patients. However, respiratory motion in the chest and abdomen can lead to uncertainty in the shape, volume, and location of the tumor, making treatment of the chest and abdomen difficult. Therefore, compensation for respiratory motion is very important in clinical treatment. The purpose of this review was to discuss the research and development of respiratory movement monitoring and prediction in thoracic and abdominal surgery, as well as introduce the current research status. The integration of modern respiratory motion compensation technology with advanced sensor detection technology, medical-image-guided therapy, and artificial intelligence technology is discussed and analyzed. The future research direction of intraoperative thoracic and abdominal respiratory motion compensation should be non-invasive, non-contact, use a low dose, and involve intelligent development. The complexity of the surgical environment, the constraints on the accuracy of existing image guidance devices, and the latency of data transmission are all present technical challenges.

Analysis of respiratory properties using the low-frequency piezoelectric sensor in patients undergoing intravenous sedation: a prospective observational study

BackgroundPatients who undergo general anesthesia may experience respiratory failure postoperatively because of respiratory depression or upper airway obstruction. AimWe investigated whether a piezoelectric sensor (AYA-P sensor) can be used to detect upper airway obstruction in patients undergoing intravenous sedation. MethodsThis prospective observational study included 26 patients who underwent dental treatment under sedation at a dental clinic. Participants were evaluated using a newly defined airway obstruction score (AOS). The AYA-P sensors were attached to the suprasternal notch and the midpoint between the umbilicus and xiphoid process. The patient's respiratory status was classified into four categories based on thoracic movements, capnography, and breathing sounds from recorded data (S1: no airflow, S2: hypoventilation, S3: normal breathing, and S4: artifact). The data obtained from the AYA-P sensors were processed using a 0.4-Hz low-pass filter, calculated using the moving standard deviation (MSD) method, and further processed using a 0.1-Hz low-pass filter (fMSD). Next, these data were differentiated (D-fMSD). We defined the positive predictive value (PPV) as fMSD or D-fMSD values higher than a threshold α in categories S1 and S2. PPV(αMAX) was defined as the maximum PPV, and the negative predictive value (NPV[αMAX]) was defined using the same αMAX. ResultsWe compared each of the apnea-hypopnea time ratio (AHT%) and AOS with PPV(αMAX) and NPV(αMAX). The AHT% and AOS were correlated with PPV(αMAX) and NPV(αMAX) in the neck and abdomen, respectively. These findings suggest that an AYA-P sensor attached to the neck and abdomen can detect a patient's respiratory status. ConclusionProcessed data obtained from AYA-P sensors can predict upper airway obstruction in patients, and the predicted data may be dependent on individual anatomical differences. Clinical trial registrationThis study was registrated in the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) clinical trial: Unique ID: UMIN000047007.

Thoracoabdominal Wall Motion–Guided Biofeedback Treatment of Abdominal Distention: A Randomized Placebo-Controlled Trial

Abdominal distention results from abdominophrenic dyssynergia (ie, diaphragmatic contraction and abdominal wall relaxation) in patients with disorders of gut-brain interaction. This study aimed to validate a simple biofeedback procedure, guided by abdominothoracic wall motion, for treating abdominal distention. In this randomized, parallel, placebo-controlled trial, 42 consecutive patients (36 women and 6 men; ages 17-64 years) with meal-triggered visible abdominal distention were recruited. Recordings of abdominal and thoracic wall motion were obtained using inductance plethysmography via adaptable belts. The signal was shown to patients in the biofeedback group, who were taught to mobilize the diaphragm. In contrast, the signal was not shown to the patients in the placebo group, who were given a placebo capsule. Three sessions were performed over a 4-week intervention period, with instructions to perform exercises (biofeedback group) or to take placebo 3 times per day (control group) at home. Outcomes were assessed through response to an offending meal (changes in abdominothoracic electromyographic activity and girth) and clinical symptoms measured using daily scales for 7 days. Patients in the biofeedback group (n= 19) learned to correct abdominophrenic dyssynergia triggered by the offending meal (intercostal activity decreased by a mean ± SE of 82% ± 10%, anterior wall activity increased by a mean ± SE of 97% ± 6%, and increase in girth was a mean ± SE of 108% ± 4% smaller) and experienced improved clinical symptoms (abdominal distention scores decreased by a mean ± SE of 66% ± 5%). These effects were not observed in the placebo group (all, P < .002). Abdominothoracic wall movements serve as an effective biofeedback signal for correcting abdominophrenic dyssynergia and abdominal distention in patients with disorders of gut-brain interaction. ClincialTrials.gov, Number: NCT04043208.

A 3D-printed phantom for stereotactic body radiation therapy simulation.

In modern radiation therapy for lung cancer, examining the uncertainty between tumor motion and beam delivery is vitally important. To lower the radiation dose delivery to the patient's normal tissue, narrowing the irradiation field margin to hit the tumor accurately is critical. Thus we proposed a phantom that simulates the thorax and lung tumor's motions by employing a 3D printing technique. The lung tumor is controlled by a linear miniature Delta robot arm, with a maximum displacement of 20 mm in each direction. When we simulated the thoracic breathing movements at 12 mm in A-P (Anterior-Posterior), the control errors were within 10%. The average tracking errors of the prosthetic tumor were within 1.1 mm. Therefore, the 3D-printed phantom with a robot arm can provide a reliable simulation for training and dosimetry measurement before lung radiotherapy, especially SBRT.

Paradoxical breathing during sleep is associated with increased sleep apnea and reduced ventilatory capacities in high-level spinal cord injury.

Sleep-disordered breathing is highly prevalent in individuals with high-level spinal cord injury. In addition, chest mechanics are known to be altered, leading to paradoxical breathing. Here we investigated the interaction between paradoxical breathing and sleep quality in these patients, and its association with measurements of respiratory function, hypercapnic ventilatory response and peak exercise ventilation. Home-based polysomnography was performed in 13 patients with spinal cord injury (C4 to T4) untreated for sleep-disordered breathing. We defined paradoxical breathing as counterphase between thoracic and abdominal movements during slow-wave and rapid eye movement sleep. Sleep quality, pulmonary function, hypercapnic ventilatory responses and peak exercise ventilation were compared between those with and without paradoxical breathing. Half of individuals presented with nocturnal paradoxical breathing. Despite similar age, body mass index, injury level, time since injury, and respiratory function, those with paradoxical breathing had higher apnea-hypopnea index (13 ± 8 versus 5 ± 3 events per hr) and average sleep heart rate (67 ± 12 versus 54 ± 4 bpm; p < 0.05). Moreover, paradoxical breathing was associated with lower hypercapnic ventilatory response (slope: 0.35 ± 0.17 versus 0.96 ± 0.38) and lower peak exercise ventilation (33 ± 4 versus 48 ± 12 L min-1; p < 0.05). Nocturnal respiratory muscle desynchronization could play a role in the pathophysiology of sleep apnea, and could relate to low ventilatory responses to both hypercapnia and exercise in high-level spinal cord injury. Polysomnography may be an important diagnostic tool for these patients for whom therapeutic approaches should be considered to treat this abnormality.

Variations in respiratory and functional symptoms at four months after hospitalisation due to COVID-19: a cross-sectional study

BackgroundMuch remains unknown about complex respiratory symptoms after COVID-19. Here we aimed to describe and analyse patients’ various respiratory symptoms 4 months after discharge from hospitalisation for COVID-19, focusing on sex, previous pulmonary disease, and prolonged mechanical ventilation.MethodsThis cross-sectional study involved five hospitals and included 52 patients with self-assessed respiratory dysfunction at 4 months after discharge from hospitalisation for severe COVID-19. Their average age was 63 years, 38% were women, 15 had a previous diagnosed pulmonary disease, and 29 were current or previous smokers. Additionally, 31 had required intensive care—among whom 21 were intubated and 11 needed mechanical ventilation for ≥20 days. Respiratory function was tested concerning lung volumes, expiratory flow, muscle strength, physical capacity (including concurrent oxygen saturation), thoracic expansion, and respiratory movements.ResultsAmong 52 patients, 47 (90%) had one or several objectively measured respiratory function abnormalities. Decreased thoracic expansion was observed in 32 patients (62%), abnormal respiratory movements in 30 (58%), decreased vital capacity in 21 (40%), low physical function in 13 (26%), and desaturation during the test in 9 (17%). Respiratory inspiratory muscle strength was more commonly diminished than expiratory strength (27% vs. 8%). We did not observe differences between men and women, or between patients with versus without diagnosed pulmonary disease, except that those with pulmonary disease had significantly lower physical capacity assessed with 6MWD (70% vs. 88% predicted, p = 0.013). Compared to those who did not, patients who required ≥20 days of mechanical ventilation performed similarly on most tests, except that all thoracic breathing movements were significantly smaller (p < 0.05). The numbers and combinations of abnormal findings varied widely, without clear patterns.ConclusionPatients with remaining respiratory symptoms 4 months after discharge from hospitalization due to COVID-19 may suffer from various abnormal breathing functions, and dysfunctional breathing that is not detected using traditional measurements. These patients may benefit from multidimensional measuring of breathing movement, thoracic expansion, and respiratory muscle strength, along with traditional measurements, to assess their symptoms and enable prescription of optimal treatment interventions and rehabilitation.Trial registrationFoU i Sverige (Research & Development in Sweden, Registration number: 274476, registered 2020-05-28).

Investigating concurrent validity of inertial sensors to evaluate multiplanar spine movement

Inertial measurement units (IMUs) offer a portable and inexpensive alternative to traditional optical motion capture systems, and have potential to support clinical diagnosis and treatment of low back pain; however, due to a lack of confidence regarding the validity of IMU-derived metrics, their uptake and acceptance remain a challenge. The objective of this work was to assess the concurrent validity of the Xsens DOT IMUs for tracking multiplanar spine movement, and to evaluate concurrent validity and reliability for estimating clinically relevant metrics relative to gold-standard optical motion capture equipment. Ten healthy controls performed spine range of motion (ROM) tasks, while data were simultaneously tracked from IMUs and optical marker clusters placed over the C7, T12, and S1 vertebrae. Root mean square error (RMSE), mean absolute error (MAE), and intraclass correlation coefficients (ICC2,1) were calculated to assess validity and reliability of absolute (abs; C7, T12, and S1 sensors) and relative joint (rel; intersegmental thoracic, lumbar, and total) motion. Overall RMSEabs = 1.33°, MAEabs = 0.74° ± 0.69, and ICC2,1,abs = 0.953 across all movements, sensors, and planes. Results were slightly better for uniplanar movements when evaluating the primary rotation axis (prim) absolute ROM (MAEabs,prim = 0.56° ± 0.49; ICC2,1,abs,prim = 0.999). Similarly, when evaluating relative intersegmental motion, overall RMSErel = 2.39°, MAErel = 1.10° ± 0.96, and ICC2,1,rel = 0.950, and relative primary rotation axis achieved MAErel,prim = 0.87° ± 0.77, and ICC2,1,rel,prim = 0.994. Findings from this study suggest that these IMUs can be considered valid for tracking multiplanar spine movement, and may be used to objectively assess spine movement and neuromuscular control in clinics.

ABOLITION OF SAGITTAL T7-T10 DYNAMICS DURING FORCED VENTILATION IN AIS PATIENTS WITH LENKE 1A CURVES

In healthy subjects, respiratory maximal volumes are highly dependent on the sagittal range of motion of the T7-T10 segment. In AIS, the abolition of T7-T10 dynamics related to the stiffness induced by the apex region in Lenke IA curves could harm ventilation during maximal breathing. The aim of this study was to analyze the dynamics of the thoracic spine during deep breathing in AIS patients and in healthy matched controls. This is a cross-sectional, case-control study. 20 AIS patients (18 girls, Cobb angle, 54.7±7.9°; Risser 1.35±1.2) and 15 healthy volunteers (11 girls) matched in age (12.5 versus 15.8 yr. mean age) were included. In AIS curves, the apex was located at T8 (14) and T9 (6). Conventional sagittal radiographs of the whole spine were performed at maximal inspiration and exhalation. The ROM of each spinal thoracic functional segment (T1-T7, T7-T10, T10-T12) and the global T1-T12 ROM were measured. In healthy subjects, the mean T1-T12 ROM during forced breathing was 16.7±3.8. AIS patients showed a T1-T12 ROM of 1.1±1.5 (p&lt;0.05), indicating a sagittal stiffness of the thoracic spine. A wide T7-T10 ROM (15.3±3.0) was found in healthy controls (91.6% of the T1–T12 ROM). AIS patients showed only 0.4±1.4 ROM at T7-T10 (36.4% of the T1-T12 ROM) (p&lt;0.001). There was a significant positive correlation between the magnitude of T7-T10 kyphosis in maximal exhalation and both FVC (% of predicted FVC) and FEV1. In conclusion, Lenke 1A AIS patients show a restriction of the thoracic spine motion with an almost complete abolition of T7-T10 ROM, a crucial segment for deep breathing. T7-T10 stiffness could explain the ventilatory limitations found in AIS patients.